Antimicrobial Protection Research Articles

Emerging Trends in Allelopathy: A Genetic Perspective for Sustainable Agriculture

Over the past decades, a growing interest in allelopathy has been recorded due to the effective use of allelochemicals as growth regulators, bioherbicides, insecticides, and antimicrobial crop protection in the sustainable agriculture field. So far, the genetic aspects of the allelopathic effects have been poorly studied, and the identification of allelopathic genes and/or genomic regions (QTLs) has become a challenge to implement specific breeding programs. Here, we review the recent genetic and genome-based research findings in allelopathy, with a particular emphasis on weed control, which is one of the major crop yield-limiting factors. We discuss the key plant–microorganism interactions, including the cross-kingdom RNAi phenomenon and the involvement of microRNAs in allelopathy. Through this review, we wanted to lay the foundation for advancing knowledge in allelopathy and uncover the areas where research is needed.

TEST OF THE COMBINED MODULE FOR WATER DISINFECTION DURING EXPERIMENTAL STAPHYLOCOCCUS INFECTION

The purpose of this study was to test the combined module for water disinfection for the presence of an antimicrobial (Staphylococcus aureus) activity in a specific liquid environment. A portable module for drinking and wastewater disinfection (patented in Georgia, GE P 2013 5987B), was taken as an analog.For the first time on the actual material (generator + infected saline) we revealed a reliable bactericidal effect on staphylococci. The intensity of the neutralization of staphylococci mainly depended on the exposure time of the generator, as well as on the initial dose of microbes, i.e., the degree of water pollution.The bactericidal effect of the module was confirmed not only in saline but also in distilled water and household tap water. We emphasize that in this experiment the non-sterile liquid was used for the first time. It also turned out that a 60-second exposure provided reliable antimicrobial protection of the liquids used within the first 6 days of the experiment.

Shielding Surfaces from Viruses and Bacteria with a Multiscale Coating (Adv. Sci. 23/2022)

Multiscale Coatings In article number 2201415, Antonio Tricoli, David R. Nisbet, and co-workers provide visual in situ evidence of the ability of water repellent coatings to protect surfaces from virus and bacteria contamination. They further reveal possible failure mechanisms of these coatings amid prolonged immersion in a liquid or due to physical damage, and use these insights to engineer an advanced multifunctional coating with superior antimicrobial protection and preserved anti-viral shielding capability.

The role of nitric oxide synthase and cystatin C in the mechanisms of antimicrobial protection in children with urinary tract infections considering the etiological factor

The aim of the study was to investigate the main etiological factors of urinary tract infections in children, the role of nitric oxide synthase and cystatin C in the mechanisms of antimicrobial protection in children with acute and chronic urinary tract infections. Materials and methods. The study groups consisted of 84 children (mean age – 10.0 ± 1.3 years). The main group was divided into subgroups: the first subgroup – 17 children with acute pyelonephritis, the second subgroup – 21 patients with chronic pyelonephritis, the third subgroup – 16 patients with acute cystitis, the fourth subgroup – 10 patients with unspecified urinary tract infections. The control group consisted of 20 relatively healthy children. The levels of inducible NO-synthase (NOS2) and cystatin C were measured by enzyme-linked immunosorbent assay. The etiological pathogen was identified in the urine of 200 patients with urinary tract infections. Results. Escherichia coli was identified as the dominant pathogen in 46.7 % of cystitis patients and in 66.6 % of chronic pyelonephritis patients. The next most frequently detected etiological agent in children with acute (27.3 % of cases) and chronic (25.6 %) pyelonephritis and unspecified urinary tract infection (32.2 %) was Enterococcus faecium. Proteus mirabilis was found in 26.6 % of patients with cystitis. The level of NOS2 in all the studied subgroups was significantly higher than that in the control group (P < 0.01). A statistically significant increase in the level of cystatin C in the main group (P < 0.05) was determined. The cystatin C-to-NOS2 ratios in the studied subgroups were 1.5–2.0 times lower than those in the control group (P < 0.05). Conclusions. The change in the spectrum of pathogens has been determined, which was a premise of the need for constant bacteriological monitoring. The development of the primary inflammatory process in the urinary tract occurred amidst a certain dysfunction of the immune system, which was manifested in an insufficient quantitative response of cystatin C, as well as high serum levels of inducible NO-synthase in the patients.

Study of Novel Peptides for Antimicrobial Protection in Solution and on Cotton Fabric.

Some new N- and C-modified biomolecular peptide analogues of both VV-hemorphin-5 and VV-hemorphin-7 with varied amino acids (Cys, Glu, His), 1-adamantanecarboxylic acid, and niacin (nicotinic acid) were synthesized by solid-phase peptide synthesis—Fmoc (9-fluorenylmethoxy-carbonyl) chemistry and were characterized in water solutions with different pH using spectroscopic and electrochemical techniques. Basic physicochemical properties related to the elucidation of the peptide structure at physiological pH have been also studied. The results showed that the interaction of peptide compounds with light and electricity preserves the structural and conformational integrity of the compounds in the solutions. Moreover, textile cotton fibers were modified with the new compounds and the binding of the peptides to the surface of the material was proved by FTIR and SEM analysis. Washing the material with an alkaline soap solution did not show a violation of the modified structure of the cotton. Antiviral activity against the human respiratory syncytial virus (HRSV-S2) and human adenovirus serotype 5 (HAdV-5), the antimicrobial activity against B. cereus and P. aeruginosa used as model bacterial strains and cytotoxic effect of the peptide derivatives and modified cotton textile material has been evaluated. Antimicrobial tests showed promising activity of the newly synthesized compounds against the used Gram-positive and Gram-negative bacteria. The compounds C-V, H-V, AC-V, and AH-V were found slightly more active than NH7C and NCH7. The activity has been retained after the deposition of the compounds on cotton fibers.

Barrier function of the skin and the role of fat-soluble vitamins in the correction of its disorders

The main function of the skin is to protect the body from negative environmental influences. The physical barrier permeability is mainly represented by the stratum corneum; however, other layers of the epidermis and the dermis are its important components. The mechanical strength of the skin is provided by intercellular contacts in the epidermis and structural proteins of the dermis. The chemical-biological barrier includes lipids, acids, natural moisturizing factor and antimicrobial peptides. Mucosal immunity system creates a barrier against infection. The microflora of healthy skin counteracts its colonization by pathogens and is vital for its immune functions. Physiological processes in the skin are closely related. A violation in one of them often leads to the formation of a whole cascade of pathological reactions affecting all the links of its protection. Vitamins A, D and E are used to correct impaired barrier function of the skin. The most pronounced effect of vitamin A (retinol palmitate) is the proliferation of epidermal cells and synthesis of extracellular matrix structures of the dermis; vitamin D (cholecalciferol) regulation of differentiation and suppression of excessive proliferation of keratinocytes; vitamin E (tocopherol acetate) antioxidant effect. The combined use of these vitamins in the composition of RadevitActive ointment affects all the main elements of the protection of the epidermis and dermis: strengthens the mechanical strength of the stratum corneum and dermis, stabilizes chemical and physical protection, including prevents the penetration of foreign substances and microorganisms, reduces transepidermal loss of water and electrolytes, reduces the damaging effect of UV, increases antimicrobial and antioxidant protection.

Providing Antimicrobial Activity and Ultraviolet Protection on Wool Fabrics Using New Coloured Materials Based on Pyrimidine Derivatives

Providing Antimicrobial Activity and Ultraviolet Protection on Wool Fabrics Using New Coloured Materials Based on Pyrimidine Derivatives

Bactericidal Properties of Low-Density Polyethylene (LDPE) Modified with Commercial Additives Used for Food Protection in the Food Industry

This study investigated the influence of commercially available food preservatives: Natamax® (containing natamycin) and Nisaplin® (containing nisin) on the antimicrobial properties of LDPE film, commonly used for food packaging. Studies have shown that the addition of 3% Natamax® or, alternatively, the addition of 5% Nisaplin® provides an LDPE film with effective antimicrobial protection. The applied biocides did not significantly affect the strength and rheological properties of LDPE. However, differences in optical properties were observed. The transparency of the samples decreased slightly with the addition of 3% or 5% Natamax® (by approx. 1% and 3%, respectively). A significant change was observed in the film haze, the addition of 5% Natamax® increased this parameter by approx. 80%, while 5% Nisaplin® increased it by approx. 19%. Both Natamax® and Nisaplin® agents can be successfully used to manufacture food packaging materials with antimicrobial protection. Natamax® showed a stronger bactericidal effect, while Nisaplin® changed other properties less significantly.

Molecular Biocompatibility of a Silver Nanoparticle Complex with Graphene Oxide to Human Skin in a 3D Epidermis In Vitro Model.

Silver nanoparticles (AgNP) can migrate to tissues and cells of the body, as well as to agglomerate, which reduces the effectiveness of their use for the antimicrobial protection of the skin. Graphene oxide (GO), with a super-thin flake structure, can be a carrier of AgNP that stabilizes their movement without inhibiting their antibacterial properties. Considering that the human skin is often the first contact with antimicrobial agent, the aim of the study was to assess whether the application of the complex of AgNP and GO is biocompatible with the skin model in in vitro studies. The conducted tests were performed in accordance with the criteria set in OECD TG439. AgNP-GO complex did not influence the genotoxicity and metabolism of the tissue. Furthermore, the complex reduced the pro-inflammatory properties of AgNP by reducing expression of IP-10 (interferon gamma-induced protein 10), IL-3 (interleukin 3), and IL-4 (interleukin 4) as well as MIP1β (macrophage inflammatory protein 1β) expressed in the GO group. Moreover, it showed a positive effect on the micro- and ultra-structure of the skin model. In conclusion, the synergistic effect of AgNP and GO as a complex can activate the process of epidermis renewal, which makes it suitable for use as a material for skin contact.

Development of Wash-Durable Antimicrobial Cotton Fabrics by In Situ Green Synthesis of Silver Nanoparticles and Investigation of Their Antimicrobial Efficacy against Drug-Resistant Bacteria.

An environment friendly and wash-durable silver nanoparticle treatment of cotton fabrics was carried out by in situ reduction of silver nitrate using Azadirachta indica leaf extract. The wash durability of the silver nanoparticles treatment on the cotton fabric was improved by pretreating the fabrics by mercerization and by adopting hydrothermal conditions of 120 °C temperature and 15 psi pressure for the in situ synthesis. The silver nanoparticle treated fabrics were characterized using scanning electron microscopy, colorimetric analysis and inductively coupled plasma mass spectroscopy. The coating of silver nanoparticles was seen to be dense and uniform in the scanning electron micrographs of the treated fabrics. An evaluation of the antibacterial efficacy of the silver nanoparticle treated fabric against antibiotic-resistant Gram-positive and Gram-negative strains was carried out. The antibacterial efficacy was found to be the highest against Bacillus licheniformis, showing 93.3% inhibition, whereas it was moderate against Klebsiella pneumoniae (20%) and Escherichia coli (10%). The transmittance data of a UV spectrophotometer (290–400nm) was used for measuring the UV protection factor of the silver nanoparticle treated fabrics. All the silver nanoparticle treated fabrics showed good antimicrobial and UV protection activity. The treatment was also seen to be durable against repeated laundering. This paper contributes the first report on a novel green synthesis approach integrating mercerization of cotton fabrics and in situ synthesis of nanoparticles under hydrothermal conditions using Azadirachta indica leaf extract for improved wash durability of the multifunctional fabric.

Glucose-Activated Nanoconfinement Supramolecular Cascade Reaction in Situ for Diabetic Wound Healing.

Supramolecular nanofunctional materials have attracted increasing attention from scientific researchers due to their advantages in biomedicine. Herein, we construct a nanosupramolecular cascade reactor through the cooperative interaction of multiple noncovalent bonds, which include chitosan, sulfobutylether-β-cyclodextrin, ferrous ions, and glucose oxidase. Under the activation of glucose, hydroxyl radicals generated from the nanoconfinement supramolecular cascade reaction process are able to initiate the radical polymerization process of vinyl monomers to form hydrogel network structures while inhibiting resistant bacterial infection. The results of the diabetic wound experiment confirmed the capacity of the glucose-activated nanoconfinement supramolecular cascade reaction in situ for potent antimicrobial efficacy and wound protection. This strategy of "two birds with one stone" provides a convenient method for the application of supramolecular nanomaterial in the field of biomedicine.

Skin Barrier Enhancing Alternative Preservation Strategy of O/W Emulsions by Water Activity Reduction with Natural Multifunctional Ingredients

Water activity (aw) as an important parameter for self-preservation can help to control microbial growth in cosmetic formulations. However, high amounts of water-binding substances are required to lower the aw enough to affect microbial growth. Since consequences for the skin barrier have been poorly studied so far, we investigated the effect of aw-lowering agents on both the antimicrobial properties of o/w emulsions and skin physiological parameters. A combination of selected natural humectants (Sodium lactate, Propanediol, Erythritol, Betaine and Sodium PCA) with a total concentration of 28 wt% in an o/w emulsion was able to reduce its aw from 0.980 ± 0.003 to 0.865 ± 0.005. The challenge test results of the aw-lowered emulsion showed a convincing microbial count reduction in potentially pathogenic microorganisms. The addition of as little as 0.5% of the antimicrobial multifunctionals Glyceryl Caprylate and Magnolia Officinalis Bark Extract further enhanced the antimicrobial effect, resulting in adequate antimicrobial protection. Moreover, twice-daily application of the aw-lowered emulsion for a period of four weeks led to a skin barrier-enhancing effect: TEWL significantly decreased, and SC hydration significantly increased. Thus, we present an opportunity to replace conventional preservatives with a natural alternative preservation strategy that has been shown to offer benefits for the skin.

Antimicrobial second skin using copper nanomesh

The functional support and advancement of our body while preserving inherent naturalness is one of the ultimate goals of bioengineering. Skin protection against infectious pathogens is an application that requires common and long-term wear without discomfort or distortion of the skin functions. However, no antimicrobial method has been introduced to prevent cross-infection while preserving intrinsic skin conditions. Here, we propose an antimicrobial skin protection platform copper nanomesh, which prevents cross-infectionmorphology, temperature change rate, and skin humidity. Copper nanomesh exhibited an inactivation rate of 99.99% for Escherichia coli bacteria and influenza virus A within 1 and 10 min, respectively. The thin and porous nanomesh allows for conformal coating on the fingertips, without significant interference with the rate of skin temperature change and humidity. Efficient cross-infection prevention and thermal transfer of copper nanomesh were demonstrated using direct on-hand experiments.

Preparation and Characterization of Antioxidant, Antimicrobial, and UV-Light Protection Film Based on Poly(vinyl alcohol) and Garlic Peel Extract

Preparation and Characterization of Antioxidant, Antimicrobial, and UV-Light Protection Film Based on Poly(vinyl alcohol) and Garlic Peel Extract

The Antimicrobial Effects of Bacterial Cellulose Produced by Komagataeibacter intermedius in Promoting Wound Healing in Diabetic Mice.

As a conventional medical dressing, medical gauze does not adequately protect complex and hard-to-heal diabetic wounds and is likely to permit bacterial entry and infections. Therefore, it is necessary to develop novel dressings to promote wound healing in diabetic patients. Komagataeibacter intermedius was used to produce unmodified bacterial cellulose, which is rarely applied directly to diabetic wounds. The produced cellulose was evaluated for wound recovery rate, level of inflammation, epidermal histopathology, and antimicrobial activities in treated wounds. Diabetic mices’ wounds treated with bacterial cellulose healed 1.63 times faster than those treated with gauze; the values for the skin indicators in bacterial cellulose treated wounds were more significant than those treated with gauze. Bacterial cellulose was more effective than gauze in promoting tissue proliferation with more complete epidermal layers and the formation of compact collagen in the histological examination. Moreover, wounds treated with bacterial cellulose alone had less water and glucose content than those treated with gauze; this led to an increase of 6.82 times in antimicrobial protection, lower levels of TNF-α and IL-6 (39.6% and 83.2%), and higher levels of IL-10 (2.07 times) than in mice wounds treated with gauze. The results show that bacterial cellulose produced using K. intermedius beneficially affects diabetic wound healing and creates a hygienic microenvironment by preventing inflammation. We suggest that bacterial cellulose can replace medical gauze as a wound dressing for diabetic patients.

Assessment of Ocimum basilicum Essential Oil Anti-Insect Activity and Antimicrobial Protection in Fruit and Vegetable Quality.

Basil (Ocimum basilicum) is a commonly used herb; it also contains essential oils and other valuable compounds. The basil oil obtained has a pleasant aroma, but also a broad spectrum of biological activity. This work reports on the chemical composition, antioxidant, antimicrobial and anti-insect activity in vitro and in situ of Ocimum basilicum essential oil (OBEO) obtained by steam distillation of fresh flowering plants. Gas chromatography–mass spectrometry, DPPH, agar and disc diffusion and vapor phase methods were used to analyze the OBEO properties. The analysis of the chemical composition of OBEO showed that its main components were methyl chavicol (88.6%), 1,8-cineole (4.2%) and α-trans-bergamotene (1.7%). A strong antioxidant effect was demonstrated at the level of 77.3%. The analysis of antimicrobial properties showed that OBEO exerts variable strength of inhibiting activity against various groups of microorganisms. The growth inhibition zones ranged from 9.67 to 15.33 mm in Gram-positive (G+) and Gram-negative (G−) bacteria and from 5.33 to 7.33 mm in yeast. The lowest measured minimal inhibition concentration (MIC) was 3.21 µL/mL against Gram-negative Azotobacter chrococcum and Gram-positive Micrococcus luteus. The antimicrobial activity of in situ vapor phase of OBEO was also confirmed on apples, pears, potatoes and kohlrabi. The highest insecticidal activity against Pyrrhocoris apterus, observed at the concentration of 100%, caused the death of 80% of individuals. Due to its broad spectrum of activity, OBEO seems an ideal candidate for preserving fruit and vegetables.

Nutritional and Medicinal Values of Dates (Phoenix Dactylifera L.) From the Perspective of Modern Medicine and Iranian Traditional Medicine

Objective Dates are one of the oldest medicinal foods that contain natural sugars (sucrose, glucose, and fructose), vitamins, minerals, phenolic compounds, and high antioxidants. There is a wide range of secondary metabolites in dates including anthocyanins, carotenoids, flavonoids, phenolic acid, procyanidin, and sterols. These bioactive compounds have antioxidant, antimicrobial, anticancer, anti-inflammatory, and liver protection properties. This study aims to investigate the medicinal and nutritional values of dates in modern medicine and Iranian traditional medicine. Methods In this review study, data were collected from traditional Iranian-Islamic medicine books (Quran, Makhzan-Al-Adviyeh) and all articles published from 2010 to 2021 in the field of clinical trials on humans and common diseases (Gynecological, cardiovascular, gastrointestinal inflammation, and brain disorders) and indexed in online databases (Google Scholar, PubMed, Ovid, MagIran) using specialized keywords. Results Due to the antioxidant properties (flavonoid and polyphenolic), dates have been recommended for cardiovascular health, fertility, reduction of inflammation, digestive health, and brain health in modern medicine, and for treating weakness, memory instability, fever, pain, nervous disorders, male and female infertility, pertussis, and bladder pain as a sedative, expectorant, laxative, and diuretic product in traditional medicine (Iranian, Greek, Roman, Chinese and Indian). In Quran (Surah Maryam), it has been mentioned that dates fruit strengthens the contractile and cervical muscles in the last months of pregnancy. It also lowers the blood pressure in pregnant women for a short time, which reduces the amount of bleeding during childbirth. Conclusion The results of studies indicate the medicinal and nutritional values of dates in improving the metabolic activities, especially the functions of heart, fertility, digestion, and brain.

Antimicrobial Tear Lipids in the Ocular Surface Defense.

The concept of antimicrobial lipids as effectors of innate host defense is an emerging field. There is limited knowledge on the antimicrobial role of lipids in the ocular environment. Tears act as first line of defense to protect the ocular surface from infections. Antimicrobial effects of tear lipids have been demonstrated using meibomian lipids that are the source of majority of lipids in tears. This article describes the knowledge available on the antimicrobial role of tear lipids at the ocular surface and the antimicrobial potential of various lipid classes present in tears that can contribute to antimicrobial protection of the eye. Like other mucosal secretions, tears contain many proteins and lipids with known antimicrobial effects. The antimicrobial defense of tears is far stronger than can be demonstrated by the effects of individual compounds many of which are present in low concentrations but synergistic and additive interactions between them provide substantial antimicrobial protection to the ocular surface. It is inferred that antimicrobial lipids play important role in innate defense of tears, and cooperative interactions between various antimicrobial lipids and proteins in tears provide a potent host defense mechanism that is effective against a broad spectrum of pathogens and renders self-sterilizing properties to tears for keeping the microbial load low at the ocular surface.

Functionalization of cotton fabrics with titanium oxide doped silver nanoparticles: Antimicrobial and UV protection activities.

The target of our current work was designed to prepare titanium oxide doped silver nanoparticles (Ag/TiO2 NPs) and their impact on the functionalization of cotton fabrics. Additionally, the effect of Ag/TiO2 NPs was compared with the individually prepared silver nanoparticles (AgNPs) and titanium oxide nanoparticles (TiO2 NPs). In this work, AgNPs were prepared in the solid state using arabic gum as efficient stabilizing and reducing agent. Then, two concentrations of the as-synthesized nanoparticles were used to functionalize the cotton fabrics by pad-dry-cure treatment in the presence of fixing agent to increase the durability of treated cotton fabrics against vigorous washing cycles. The findings implied that the as-prepared nanoparticles were successfully synthesized in nano-size with spherical shape and homogeneity. The efficacy of the functionalized cotton fabrics with those nanoparticles were evaluated in terms of multifunctional properties including antimicrobial and ultraviolet protection factor (UPF) and the mechanical features before and after many washing cycles; 10, 15 and 20 times. The resultant also proved that Ag/TiO2 NPs-treated cotton fabrics exhibited the greater values of both antimicrobial and UPF properties with enhancement in the tensile strength and elongation features. Thus, the combination between these two nanoparticles through doping reaction is suitable for imparting superior antimicrobial properties against the four tested microbial species (Staphylococcus aureus, Escherichia coli, Candida albicans, and Aspergillus niger) and good UPF properties. Depending on the promising obtained results of the multi-finishing fabrics, these nanoparticles of Ag/TiO2 NPs can be applied for the production of an efficient medical clothes for doctors, nurses and bed sheets for patients in order to kill and prevent the spread of bacteria and then, reduce the transmission of infection to others.

Evaluation on physicochemical properties and stability of Thanaka bark powder for natural face powder products

Thanaka (Hesperethusa crenulata Roem.) has been traditionally applied as cosmetics in Myanmar and the northern of Thailand [1] and exhibited anti-oxidant, anti-inflammatory, anti-microbial, skin lightening, and sun protection properties [1-4]. Thanaka’s specifications for cosmetic development are sparse to be presented, although its flowability was reported [1]. Of which, the bark was more suitable than the stem for solid dosage form development [1]. Thus, this study was aimed to assess the physicochemical properties and stability of Thanaka bark powder. The yellowish light brown powder (L* = 75.63 ± 0.01, a* = 5.58 ± 0.02 and b* = 23.45 ± 0.02) (Figure 1A) with bulk and tapped densities of 0.25 ± 0.00 and 0.29 ± 0.00 g/mL, was able to absorb water and oil (17.31 ± 0.77% and 13.39 ± 0.29%). The powder was ICP-MS proved to be uncontaminated with heavy metals prohibited for cosmetics. The powder morphology was plate-like crystals with fractured as SEM observed (Figure 1B). Thermal properties examined by DSC resulted in glass transition, crystallization and melting temperatures of 66.43, 70.25 and 73.39°C, with 51.32 ± 4.13% of crystallinity by XRD. The color (ΔE ≤ 1.43 ± 0.04), morphology, thermal properties, water absorption capacity and oil absorption capacity slightly shifted following to 3-month storage under ambient temperature and 45°C.